The principlism of informed consent emphasizes the ‘rational ego’and ‘right action’. The existence of the ‘rational ego’ that doctor and the patient as separate individuals which leads to a state of separation of the doctor-patient relationship; ‘right action’which makes people dependent on external rules leads to a weakening sense of internal responsibility. This paper attempts to solve the problem of the principlism of informed consent through Martin Buber's relational ethics. Martin Buber proposes a relational ethics differentiated between ‘I-It’ and ‘I-Thou’, focusing on the dialogue relationship between people. From the perspective of Martin Buber's relational ethics, this paper discusses in detail three special ethical issues in terms of competence, information and decision-making of informed consent for xenotransplantation. Finally, in the face of the uncertainty of xenotransplantation, this paper proposes that informed consent is based on the mutual conversion between ‘I-Thou’ and ‘I-It’, and takes the relationship of ‘I-Thou’ as the core to realize the positive effect of others responsibility.